FIG. 16 is a sectional view of a conventional speaker disclosed in Unexamined Japanese Utility Model Publication No. 57-111196. Permanent magnet 1 is sandwiched between upper plate 2 and yoke 3 to form magnetic circuit assembly 4. Frame 6 is fitted to yoke 3. The outer periphery of edge 9 is attached onto frame 6. Voice coil 8 attached to diaphragm 7 is placed in magnetic gap 5 in magnetic circuit assembly 4. Diaphragm 7 and edge 9 along the outer periphery of diaphragm 7 are unitarily formed of one resin film sheet.
The problem with the above speaker is that its performance is deteriorated when the speaker is downsized to meet market requests, because the size of diaphragm 7, edge 9, or permanent magnet 1 must be reduced.